This paper describes part of the work being carried out by CRES, in the frame of the EU-funded JOULE project “PRECis : assessing the Potential for Renewable Energy in Cities”. The main aim is to develop simplified parameters that describe the microclimate and environmenal performance of different urban textures. One of the roles of CRES within the team is to describe simplified parameters for the use of vegetation in the urban context, which can eventually be used irrespective of site-specific characteristics for different climatic contexts and urban textures. Of particular interest is the effect of vegetation on microclimate : thermal effects, as well as the effect of vegetation on solar and daylight access. These affect the microclimate of the existing open spaces as well as the energy use of the surrounding buildings for heating, cooling and lighting, through shading, evapotranspiration, etc. Simple parametric studies are examined, to identify the thermal impact of vegetation in the urban environment, at the scale of the urban block, particularly as far as the reduction of air temperature is concerned.
Vegetation in the urban environment : Microclimatic analysis and benefits
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Comfort in urban spaces : Defining the boundaries of outdoor thermal comfort for the tropical urban environments
With rapid urbanisation, often without climate responsive guidelines, cities in the Tropics are progressively falling short of sustaining outdoor life. In order to re-establish and sustain life outdoors, it is important that we try to make urban spaces comfortable as far as the ambient climate permits. In order to ascertain conditions of comfort for outdoor spaces, we need to define comfort for outdoors. This paper presents findings on outdoor comfort based on field investigations conducted in Dhaka, a city in the wet-Tropics. Findings from a survey conducted on a large number of randomly selected people from urban spaces are presented. The findings include factors affecting comfort outdoors for Dhaka and a comfort regime based on environmental parameters for urban outdoors is presented. Interestingly, comfortable ambient climate leads to comfortable indoor environment, particularly with regard to free running buildings. With regard to mechanically controlled indoor environments, a comfortable outdoor produces lesser stain on energy environment relationship. By defining conditions of comfort for outdoor environments, an important step towards achieving sustainability of our urban environments can be made.
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Modelling thermal adaptation and thermal preferences in outdoor urban environments
Whilst research into indoor thermal comfort is well advances, the impact of outdoor thermal conditions has received less attention. The thermal conditions encountered in outdoor urban space are a major determinant of the patterns of usage of the space and are created in part by the surrounding buildings. This paper describes a research project which is attempting to develop indices of outdoor thermal comfort which can be used in the evaluation of the impact of new urban development upon the quality of the environment in urban spaces.
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Comfortable and/or pleasant ambience : conflicting issues ?
We present here a theoretical study about the relationships between comfortable and pleasant ambiences. The notion of comfort is not sufficient for the study and design of ambience. Ambience is defined here as the way the environment affects a subject. Subjects are naturally affected by a global ambience. However, for the analysis, we distinguish between luminous, aesthetic, thermal, acoustic… ambience. Comfort definitions exclude the notion of tension and psycho-physiological disturbance on subjects, whatever its level may be. The question of pleasant ambience is naturally not fully answered. However, one way to define a pleasant ambience especially includes the notion of tension on subjects affected by an ambience. The case of the house on the cascade by F L Wright perfectly illustrates this point. This house is situated on a waterfall whose acoustic level is above all norms. Therefore this house is not comfortable. However, it is widely recognised and taught as a reference for its pleasant ambience, especially for the contribution of the acoustic ambience. In this case, the comfortable and pleasant sides of ambience are conflicting. As modern technologies are improving, artificial lighting and ventilation, for example, can lead to perfectly comfortable ambience. However, it is widely recognised that natural lighting and passive ventilation are more pleasant. We develop this discussion on the basis of the results of a study on qualifications of luminous ambience and on other theoretical and technical works. We believe that this investigation is nowadays important because the technological sides of ambience are improving : comfortable ambience may be designed, but are they pleasant ? We think that a very global view on ambience is now needed.
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Daylighting quality through user preferences : Investigating libraries
This paper presents the findings of a research project investigating daylighting quality through its perceived effect on the everyday user of a space. The subjects participating in the experiments are asked to describe their perception of the daylit environment through a standard questionnaire. The physical measurements taken in these daylit spaces are then correlated with the subjects’ sensations, in order to identify which quantifiable parameters affect daylighting quality and others which are non quantifiable. The main results suggest that quality is in fact the main criterion by which users judge the daylighting in a space. A new index named LD is derived, which correlates successfully with user responses. The paper concludes by presenting the impact of the findings on daylighting design.
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CO2 emission concerning daily activities in residences
It is important that the countermeasures to reduce CO2 emission during the housing usage phase be examined. In this study, the factors under various daily activities concerning the CO2 emission were simulated, in order to examine a more effective countermeasure. Then, it was confirmed that CO2 emission, that can be controlled by residents, occupies a large portion. For this reason, it was also found that the life style influenced the amount of CO2 emission considerably. These results suggest that the improvement of the residential life style is important for the general reduction of the CO2 emission.
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A GIS framework for studying post-occupancy climate-related changes in residential neighbourhoods
A GIS-based methodology is discussed, which simplifies recording and analysis of post-occupancy changes in residential buildings. Each modification is considered as a unique record in a database, and has a string assigned to it in a multi-parametric matrix. Its position in the matrix is determined by functional relationships with other housing modifications, orientation, adjacent inner and outer spaces, building materials and physical size. The method was tested in three residential neighbourhoods in two towns in the Negev desert of Israel, with the intention of highlighting modifications related to the climatic performance of buildings, and developing a set of recommendations aimed at improving the design of new residential buildings.
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Building in the climate of the New World… A cultural or environmental response?
The reciprocity between appearance, available technology and environmental context forms the subject matter of Rappaport’s famous ‘House Form and Culture’. In this essay the evolution of a particular seventeenth century building type – the English ‘hall-and-parlour’ house – in response to the significant environmental and cultural change experienced by the first English settlers in Massachusetts is examined in detail, with the aim of clarifying the impact of climatic conditions on individual buildings and larger settlement patterns. It demonstrates that transformations in the idea of what a house might look like, particularly in relation to its immediate surroundings, had wider repercussions for American ‘society’, and for energy expenditure on transport, in the longer term.
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Environmentally sensitive design in practice
A new university campus in outback Australia is set to teach the world how to not only survive, but to sustain life in the future. Built to house the School of Environment and Information Sciences and the School of Business, the campus is also a centre for the study of environmental issues. Academic offices, a research institute, regional herbarium, specialist teaching facilities, lecture theatre complex and computer centre are occupied and residential accommodation will be complete in February 2000. Set on an open site, the campus comprising elements disciplined by deep green ethics, is articulated with rammed earth and recycled timber clearly expressing the Universitys environmental mission. Water is one of this dry hot continents most precious resources. The award winning, stormwater recycling system, on-site greywater treatment and dry composting toilets obviate the need for connection to town sewerage or stormwater mains. Early decisions favouring passive techniques were critical in developing a building envelope responsive to temperature variations. The thermal mass of the concrete floors and rammed earth walls stores the suns heat in winter and keeps the building cool in winter. Low energy systems include night cooling, circulation of hot and cold water through the slab, waterfalls and spray mists, thermal chimneys. The Thurgoona Campus experience is on a neighbourhood scale and provides a live model that addresses some of the present and future issues of environmental impact and community cost.
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The effect of design parameters on environmental performance of the urban patio: a case study in Lisbon
The focus of the paper is on the effect of design parameters on environmental performance of the urban patio. This paper presents the results of a case study of different courtyards in Lisbon. Short-term monitoring was undertaken to assess the effects of design parameters, such as geometry, orientation and finishings on environmental performance of four different patios. Air temperature was recorded for eight days during August 1996 and spot measurements of air velocity were taken. The results are compared and discussed. The paper also examines the results of solar radiation studies carried out to assess possible improvements in courtyard thermal performance.
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